Rheological Properties of Mixed Aqueous Solutions of Geminis (12‐3‐12,2Br−) and SDS

The rheological properties of surfactant solutions are the main parameter that affects the surfactant application. In this work, the rheology of the mixed system 12‐3‐12,2Br^?/SDS/H₂O was discussed particularly. The relationship between the microstructure of surfactant aggregates and rheology of mixed solutions was explored. It is shown that the rheological properties of solutions have different behaviors at different molar ratio of two surfactants under given total concentration. With the increase of molar ratio (12‐3‐12,2Br^?/SDS), the solution change from Newtonian liquid into positive thixotropy then to negative thixotropy, at last turn to positive thixotropy again, and ATPS becomes the dividing line. The difference of rheological properties is the embodiment of difference for surfactant aggregates' microstructures. The cryo‐TEM results shown that the solutions containing aggregates with big size, such as rodlike micelles, multilamellar micelles, show positive thixotropy. However, the solutions containing lamellar micelles or liquid crystal will show negative thixotropy. The positive thixotropy endows the mixied system a potential application in enhanced oil recovery.     

Micellization and Interaction Properties of Aqueous Solutions of Mixed Cationic and Nonionic Surfactants

The micellization process of binary surfactant mixtures containing cationic surfactants viz. dodecyl pyridinium halide (C₁₂PyX; X=Cl, Br, I), tetradecyl pyridium bromide (C₁₄PyBr), and hexadecyl pyridium halide (C₁₆PyX; X=Cl, Br) and a nonionic surfactants viz. dodecyl nonapolyethylene glycol ether (C₁₂E₉), dodecyl decapolyethylene glycol ether (C₁₂E₁₀), dodecyl dodecapolyethylene glycol ether (C₁₂E₁₂), and dodecyl pentadecapolyethylene glycol ether (C₁₂E₁₅) in water at different mole fractions (0–1) were studied by surface tension method. The composition of mixed micelles and the interaction parameter, β evaluated from the CMC data obtained by surface tension for different systems using Rubingh's theory were discussed. Activity coefficient (f₁ and f₂) of cationic surfactant (C_nPyBr)/C₁₂E_m (n=12, 14, 16 and m=10, 12, 15) mixed surfactant systems were evaluated, which shows extent of ideality of individual surfactant in mixed system. The stability factors for mixed micelles were also discussed by Maeda's approach, which was justified on the basis of steric factor due to difference in head group of nonionic surfactant.     

两性聚电解质PDMA_m-b-PAA_n与表面活性剂(12-6-12)的相互作用

采用Zeta电位、荧光探针、表面张力和黏度等方法研究了碱性条件下不同嵌段比的两性聚电解质聚(N,N-二甲胺基甲基丙烯酸乙酯-b-丙烯酸)(PDMAm-b-PAAn)与阳离子偶联表面活性剂(C12 H25(CH3)2N(CH2)6N(CH3)2C12H25·2Br-)(简称12-6-12)的相互作用.结果表明:由于静电相互作用,两嵌段聚电解质PDMAm-b-PAAn和12-6-12之间可形成类胶束或复合物,PDMA链段的弱亲水性对复合物起到稳定的作用.对同一类型的两嵌段聚电解质,改变两链段的相对长度之比,既不会使其在溶液中的构象发生改变,也不会使其与表面活性剂的相互作用模式发生改变.     

Interaction of Anionic Gemini Surfactants with Other Surfactants

The interaction of anionic gemini surfactants with other surfactants (such as anionic, cationic, nonionic) was systematically overviewed, paying attention to synergism observed in various properties. These mixed systems were found to show remarkable synergism in micelle formation. The critical micelle formation values being lower than the individual gemini surfactants indicate that the mixed micellization is due to attractive interaction between the two components. Almost all combinations were discussed in terms of respective surface tension reduction effectiveness and surface tension reduction efficiency and aggregation number for evaluation of synergism.     

正离子Gemini表面活性剂/负离子聚电解质相互作用的研究

摘要 采用荧光探针法和电导法研究了正离子偶联表面活性剂(C₁₂H₂₅(CH₃)₂N-(CH₂)₆-N(CH₃)₂C₁₂H₂₅•2Br) (12-6-12•2Br^－)和带相反电荷聚电解质聚丙烯酸钠(NaPA)的相互作用, 结果表明: 由于静电相互作用, 12-6-12•2Br^－和NaPA之间可以形成类胶束或复合物. 对比十二烷基三甲基溴化铵(DTMAB)与NaPA复配体系的荧光光谱, 发现偶联表面活性剂与NaPA的相互作用强于传统表面活性剂. 此外, 还研究了盐和醇对偶联表面活性剂/聚丙烯酸钠的复配体系微极性的影响, 发现盐和醇对表面活性剂在聚电解质上形成类胶束和复合物的溶解都有一定的促进作用.     

Analysis of the Interactions of Polyvinylpyrrolidone with Conventional Anionic and Dimeric Anionic Surfactant

Classical physical method has been applied in the present study of interaction between water soluble polymer with anionic dimeric and conventional anionic surfactants. Micellization activity of carboxylate-based anionic dimeric (CAD) as well as sodium dodecyl sulfate (SDS) surfactants in the presence of nonionic polymer, that is, polyvinylpyrrolidone (PVP), has been studied through conductometric and surface tensiometric measurements. From these methods the critical aggregation concentrations (CACs), critical micelle concentrations (CMCs), and the effective degree of counterion binding (β) were determined. For the evaluation of behavior of CAD toward the PVP various thermodynamic properties viz. standard Gibbs energy of micellization, standard enthalpy, and entropy of micellization of CAD/PVP mixed system have also been estimated and discussed. The results exhibit that anionic dimeric surfactant interacts strongly with PVP as compared to conventional surfactant.     

磺基甜菜碱两性表面活性剂的结构性质

用量子化学中的密度泛函理论, 在B3LYP/6-31＋G*水平上, 对十二烷基磺基甜菜碱分子进行了结构优化, 在分子水平上研究了两性表面活性剂与阳离子(Ca^2＋)、阴离子(Cl^－)之间的相互作用. 计算结果表明: 两性表面活性剂的负电荷中心采用2∶1型, 即极性头中两个氧原子与阳离子发生稳定结合|而正电荷中心采用侧方, 即N原子的两个亚甲基和一个甲基与阴离子发生稳定结合. 由于桥联亚甲基和α-亚甲基均带有一定数量的电荷, 因此两性表面活性剂中正负电荷中心需要根据亚甲基上电荷多少进行划分. 计算也发现, 表面活性剂尾链带有部分弱电荷, 使胶束内核带有了部分极性, 利于表面活性剂在溶液中的聚集, 此种极性介于烷烃油相和水相的极性之间.     

Mixed micelles of cetyltrimethylammonium bromide and poly(ethylene glycol)-600 monolaurate as catalysts of polyethylenimine phosphorylation in chloroform

Micelle formation in a cetyltrimethylammonium bromide-poly(ethylene glycol)-600 monolaurate-chloroform system in the absence and presence of hydroxybenzylated polyethylenimines (PEI) was studied by dielcometric titration, NMR self-diffusion, light scattering, and kinetic methods. A catalytic effect of mixed micelles on the reaction of 4-nitrophenylbis(chloromethyl)phosphinate with PEI was shown. The catalytic effect depends on the degree of substitution of PEI and composition of a surfactant mixture. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1359–1365, August, 2006.     

Energetics of sodium dodecylsulfate-dodecyldimethylamine oxide mixed micelle formation

Enthalpies of dilution and osmotic coefficients of the sodium dodecyl-sulfate (NaDS)-dodecyldimethylamine oxide (DDAO) mixtures in water have been measured at 25 and 37°C, respectively. From the enthalpies of dilution the apparent molar relative enthalpies L were calculated. The change of the L vs. total molality m_t profiles with the mole fraction reflects the variation of the ionic character of the mixed micelles. From the osmotic coefficients the nonideal free energy G ₂ ⁿⁱ were calculated. By combining G ₂ ⁿⁱ with the partial molar relative enthalpies, the nonideal entropies TS ₂ ⁿⁱ were determined. At a given mole fraction, G ₂ ⁿⁱ and TS ₂ ⁿⁱ values are decreasing and increasing respectively, tending to become constant at high m_t. The excess properties for the mixed micelle formation were evaluated as a function of the mixture composition at some m_t. The profiles are compared with those obtained from thermodynamics of binary liquid mixtures and the regular solution theory.     

A Study of the Solubilization of Polar Oily Materials by Alkyl Polyglucoside and Sodium Dodecyl Sulfate in Mixed Surfactant System

The effects of different alkyl chains of nonionic surfactants and solubilized polar oily material on the solubilizing capacity of binary anionic‐nonionic mixed surfactant systems were studied. This system includes surface tension measurements to determine the critical micelle concentration. Results were analyzed using regular solution theory to obtain the mixed micelle and the interaction parameter β, in order to evaluate the type of interactions of surfactants in the mixed micelle. Solubilizing capacity has been investigated by measuring the optical density of solubilized polar oily materials like octanol, decanol, and dodecanol. The solubilizing phenomenon exhibited by mixed surfactants systems showed better results than that of the individual surfactant system. The amount of solubilization in mixed surfactant increases with increase in carbon chain length of alkyl polyglucoside.